20 Hurt At Pennsylvania High School After Stabbing Spree

Screenshot/CBS Pittsburgh
A male student reportedly went on a stabbing spree Wednesday morning at Franklin Regional High School in Murrysville near Pittsburgh.

Twenty people were injured, most of them students. Four victims with serious injuries were flown by medical helicopter to area hospitals.

The victims' injuries are not thought to be life-threatening, emergency management official Dan Stevens said at a press conference.

Victims were as young as 14 years old.

Police have a suspect in custody who hasn't yet been identified. The suspect is believed to be a 16-year-old male student. He reportedly had two knives and stabbed students in first-floor classrooms and hallways at about 7 a.m. as students were arriving for school.

The school district posted this message on its website:

A critical incident has occurred at the high school. All elementary schools are canceled, the middle school and high school students are secure.

Students are being reunited with their families at another school, Stevens said.

Stevens added that it's unclear how the suspect was taken into police custody, but the Pittsburgh Post-Gazette reports that an assistant principal tackled him.